DEC VT05 with OS/8 -- basic system rebuild?

From: "Philipp Hachtmann" Sent: Tuesday, May 12, 2009 11:31 PM If your concern is the large software base that does something like TSF; JMP .-1; TLS to output a character, then yeah, you'll need hardware line-feed delay. Per the KL8J/M8655 documentation: " Fill Characters -- VT05 To operate at speeds above 300 baud, the VT05 requires that filler characters be transmitted to it followeing any line feed character. The insertion of the "FIL" jumper on the M8655 causes four all zero characters to be automatically transmitted to the VT05 following every line feed. The transmit flag is not set until the KL8-JA is ready to accept other data. " There doesn't seem to be any equivalent provision for the KL8E/M8650, or (surprisingly) the DKC8/M8316. So I think your easiest solution for an 8/e/f/m/a is to install an M8655. For earlier machines, the M707 transmitter module has a "wait" input, which is designed to hold off a half-duplex line, but which I believe could be adapted to do what you want. You'd have to add a couple of chips somewhere (effectively modifying or replacing the M707), though. If the VT05 dropped DSR or some similar signal during the interval that it is not ready, it would make things a lot simpler. I don't see the circuitry to do that in the VT05 schematics, though. Vince